1. Field of the Invention
This invention relates generally to inflatable-type modular occupant restraint systems for passenger vehicles or, as they are more commonly known, air bag restraint systems. More particularly, this invention relates to an improved means for quickly securing a driver side inflator to an air bag module.
2. Description of Related Art
An air bag restraint system typically includes a canister, which has an open side and encloses an inflator and at least part of an air bag, and a cover which conceals the module from view. A driver side air bag module is typically mounted in the center of the steering wheel behind a protective cover. When the air bag module is designed for the passenger side of a vehicle, the container may be located just behind the vehicle dashboard, cosmetic cover, or passenger side instrument panel (hereinafter referred to as "dashboard") and the cover may form an integral part of the vehicle dashboard.
When the vehicle is involved in a collision, a crash signal initiates operation of the inflator to cause the air bag to deploy. The inflator produces an inert gas (e.g., nitrogen) which is directed under pressure into the air bag to force the air bag out of the canister incorporated in the module and into the passenger compartment of the vehicle. As the air bag is forced out of the module the pressure exerted on the driver side cover or dashboard causes selected portions of the cover or dashboard to separate, in a predetermined manner along tear seams or breakaway seams (hereinafter referred to as "tear seams") to enable the air bag to be directed into the passenger compartment.
In the conventional mounting of a driver side air bag inflator to a module housing, the air bag cushion is attached to one side of a module housing with a retainer ring. The air bag inflator is attached to the opposite side of the module housing from the air bag cushion with bolts secured with nuts. The installation of the inflator in an air bag module requires a number of fastening steps and machine steps to secure the inflator, which installation step increases the cycle time for the manufacture of a module. Further, the use of fasteners to attach the inflator to an air bag module is a major cause of reworking of the inflator module assembly due to the necessity of replacing broken or unsecured fasteners. Reworking of the inflator module is not always possible. In these situations the defective modules must be discarded, resulting in lost production and increased manufacturing costs. The elimination of fasteners in the manufacture of the air bag module assembly would eliminate a major cause for reworking and disposal of defective inflator modules. Further, a simplified attachment system which would permit easy removal of the inflator without the need for special tools would reduce the cost and time associated with reworking of the module should removal become necessary.